Not only is it accessible to search, being both an artifact and a creature, but it is also removal on a stick
If you're killing off your tokens, you can force everyone else to do the same
To exploit those strategies, you need to fill your graveyard, and Golgari Grave-Troll is one of the best ways to do so
You can play one of those spells until the end of the turn by paying life equal to their mana cost
During the Energy period of Standard ( Kaladesh and Aether Revolt ), which were the sets before Amonkhet , there was a powerful Temur Energy deck that had multiple cards from it eventually banned - Rogue Refiner and Attune with Aether, specifically
Slithering Shade is mid-tier for shades, for what thats worth